quick-turn boards

Who is good for really quick-turn double-sided PC boards? 2 or 3 days delivered.

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Reply to
John Larkin
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mandag den 10. august 2020 kl. 21.31.59 UTC+2 skrev John Larkin:

your tormach ?

Reply to
Lasse Langwadt Christensen

That's an option. The circuit is pretty simple!

Reply to
John Larkin

mandag den 10. august 2020 kl. 22.08.33 UTC+2 skrev John Larkin:

yeh, looks like a few holes and an outline, wouldn't take more than a few minutes

Reply to
Lasse Langwadt Christensen

I think he left out of the drawing the 0.1" spaced holes in the perf board.

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  Rick C. 

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Reply to
Ricketty C

We'll do a PCB, with proper plated holes, silk, solder mask, all that.

The layout is done!

My contract layout guy suggests sierra circuits or rushpcb or sunstone. We'll get quotes for 30 or so.

Reply to
John Larkin

mandag den 10. august 2020 kl. 23.35.19 UTC+2 skrev John Larkin:

if you want to nitpick, you should move one of the wires to the other end of the board so all the caps have the same trace length and share current

Reply to
Lasse Langwadt Christensen

One of my guys started on a PCB layout and another headed for the Tormach.

Tormach won.

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He doesn't mind doing 25 this way.

Reply to
John Larkin

Either Sunstone or Advanced Circuits is fine for domestic quick-turn work. Or WellPCB for those with finite budgets who can wait a week or two.

I prefer Advanced Circuits over Sunstone these days because Sunstone's silkscreen capabilities are stuck in the Fahnestock-clip era.

-- john, KE5FX

Reply to
John Miles, KE5FX

.

Sunstone screwed me over years ago and I will never work with them again. They kept misplacing my order so I had to give them the credit card number three times with days delay each time. Then when I got the boards back the y were around 30-40% x-outs and the ones they passed kept opening vias. Fo rtunately I had plenty of spares. But I also ordered the test fixture from them and that had the same problems with open vias even as late as a decad e. Any time the test fixture exhibits flakiness I debug the symptoms and t rack it down to add a wire. They have many wires now, but at least they mo stly keep working.

A horrible company to do business with. Sunstone, ptui!

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  Rick C. 

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Reply to
Ricketty C

DIY is the way to go, especially if you can "cheat" the PTH with compoonent leads.

Reply to
Robert Baer

I posted the Tormax-milled pic above. The caps solder to giant copper islands, and he used pushed-in and soldered faston tabs for the wire connections. We'll do that.

We have shipped one unit that needs to be upgraded in the field, and the customer is willing to solder, before they run it full blast.

The TI class-D amp, TPA3255, does not specify DC offset; driving a loudspeaker, a little DC doesn't matter. But there is enough to saturate a toroid, hence the blocking caps. A couple of unfortunate events resulted in the caps being undersized at worst-case load.

It's hard to find reasonable sized or cost caps with more than a couple of amps of AC current rating, hence six in parallel. The TI chip can output 17 amps peak.

This is the worst thing that happened in this box. Most stuff worked first try, with only minor tweaks. Not a single cut/jumper.

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This is our first use of an ST Arm, which we are using now that the NXP parts seem to be going EOL. I hate when people do that, dump on their customers.

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John Larkin         Highland Technology, Inc 

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Reply to
jlarkin

Which ones are going away? We use a lot of LPC845s and LPC804s, and are looking at using one of the NXP M4F/M0+ parts.

The ST factory headers are hideous. What toolchain are you folks using with the ST parts?

Cheers

Phil Hobbs

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Reply to
Phil Hobbs

LPC3250, and I think some of the 1768 series.

I'll ask Paul the next time he's in. He has said some baddish stuff about their libraries. But first time on a new CPU, things happen.

He wrote a boot loader that we jtag into the STM32F207IGT6. We might eventually have a distributor do that. At powerup, the boot reads a plug-in serial flash chip that has the specific runtime code and the FPGA image.

We can email upgrade files to a customer, or we can send him a new physical flash plugin thing, so one of his techs can just replace it.

The ST is nice in some ways. It's very versatile about pin assignments and has lots of goodies on chip. As usual in uPs, the ADC is pretty bad.

I'd like to move more to ZYNQs and PicoZeds for anything that has an FPGA or DRAM. PicoZed is slick. I should have used that on my alternator box.

Reply to
John Larkin

Any qualification on "pretty bad". We are not seeing any problems so far. A programmer is presently collecting some data to verify some claims of the ADC being nonlinear at the top and bottom.

I'll share the results if anyone is interested.

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  Rick C. 

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Reply to
Ricketty C

Thanks, good info.

We do something similar--Simon wrote a bootloader that can flash the 845 over half-duplex MODBUS, which is pretty slick. The stock BL can do it over full-duplex UART, SPI, or SWD. We're using it in the sensors in my "connectors for high vibration" thread.

I've heard lots of good things about the silicon, and the prices are good, but the support appears to be forum-based only. That would make IAR or somebody else's toolchain attractive at some point. You don't have to spend many days stuck to pay for that.

We'll check it out.

Cheers

Phil Hobbs

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Reply to
Phil Hobbs

System workbench, it is eclipse and GCC

cubemx is a useful for getting the pin mapping correct

Reply to
Lasse Langwadt Christensen

The STM build in bootloader can flash from UART/USB/I2C/SPI/CAN

Reply to
Lasse Langwadt Christensen

In half-duplex? That's the parlour trick.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs 
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Reply to
Phil Hobbs

nope, but more interfaces, but I'd guess the nxp can do those too

Reply to
Lasse Langwadt Christensen

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